Certain touch sensor devices operate by way of capacitance sensing utilizing capacitance sensors. The capacitance detected by a capacitance sensor changes as a function of the proximity of a conductive object to the sensor. The conductive object can be, for example, a stylus or a user's finger. In a touch sensor device, a change in capacitance detected by each sensor in the X and Y dimensions of the sensor array due to the proximity or movement of a conductive object can be measured by a variety of methods. Regardless of the method, usually an electrical signal representative of the capacitance detected by each capacitive sensor is processed by a processing device, which in turn produces electrical or optical signals representative of the position of the conductive object in relation to the touch sensor pad or touch sensor screen in the X and Y dimensions.
One type of touch sensor device is a capacitive touch screen. A capacitive touch screen is an electronic visual display that can detect the presence and location of a touch within the display area. A touch screen enables one to interact directly with what is displayed, rather than indirectly with a cursor controlled by a mouse or touchpad. The touch screen lets a user do so without requiring any intermediate device that would need to be held in the hand (e.g., a stylus, although touch screens may be able to function with a stylus). Such displays can be attached to computers, or to networks as terminals. They also play a prominent role in the design of digital appliances such as the personal digital assistant (PDA), satellite navigation devices, mobile phones, and video games.
A touch screen may display an image generated by a program running on the computing device implementing the touch screen. The image may include one or more controls which a user may interact with in order to cause the program to perform corresponding actions. The controls may include, for example, an icon that the user selects by pressing the touch screen with a finger in the location where the icon is displayed. In the case where a number of controls are condensed into a relatively small area on the touch screen, or where the controls themselves are smaller than the fingertip of a user, it may be difficult for the user to accurately select the desired control. For example a user may press an area on the touch screen that overlaps more than one control, possibly resulting in the selection of an unintended control.